The present invention relates to reels used for holding packs of tape in information storage systems.
Tape, such as magnetic tape or optical tape, is commonly used to store information due to its reliability, cost efficiency, and ease of use. Tape may be made more useful and cost-effective by increasing the density of information stored and decreasing the time required to access this information. Tape may be made wider and data tracks written on the tape narrower to increase the real density of information stored on the tape. Tape may be made thinner to increase the volume of information stored on a given reel of tape. Tape may be moved past the tape head faster to increase the rate of information transferred. Tape paths may be shortened to decrease access time, decrease costs, and decrease the size and complexity of tape access systems. These factors generally necessitate an increase in performance from all elements in a tape system.
Tape is typically wound on one or two reels in a protective housing, such as a cassette or cartridge. A reel typically includes a cylindrical hub about which tape is wound to form a tape pack. Flanges are typically attached to either end of the hub and extend beyond the tape pack to guide and protect the tape. The spacing between flanges is greater than the width of the tape to allow for manufacturing tolerances in flange spacing, tape width and the planarity of various guide elements of the tape path as well as to avoid damaging the tape edges. Hence, as the tape is wound onto the hub, uneven wrapping known as stagger wrap or pack shift may result. Stagger wrap and tape shift cause the tape to enter the tape path at varying elevations. This creates problems for accurately guiding the tape within the tape transport path as well as creating the potential for excessive tape edge-to-tape guide contact, resulting in tape edge damage. Since many tape paths use one or both tape edges as a physical positioning reference, tape edge damage degrades the ability of the tape drive to alight read/write heads with magnetic tracks on the tape, ultimately degrading data integrity.
These problems are worsened by higher tape speeds, wider tapes, thinner tapes, smoother tapes, or more flexible tapes due, in part, to the build up of air films between wrap layers. Additional problems may result from impacts to the tape storage container that are transmitted through the flanges to the tape pack. Tape edges protruding beyond the tape pack may be subject to bending, kinking, or other forms of mechanical damage.
What is needed is an improved tape reel. The tape reel should accurately guide tape into the tape pack without damaging tape edges. The tape reel should also compensate for any manufacturing variances in reel construction, tape width, and the tape transport system. The tape reel should cushion shock received by the tape housing. The tape reel should physically stabilize the tape pack during long term archive storage. The tape reel should be economical to produce and should operate in existing housings and with existing tape transport systems.
It is an object of the present invention to provide an aligning force to tape as it spools and unspools.
It is another object of the present invention to permit trapped air to bleed out from between tape layers in a tape pack.
It is still another object of the present invention to minimize the effect of manufacturing tolerances in a tape reel, tape, and tape transport system.
It is yet another object of the present invention to provide protection to a tape pack from mechanical shock.
It is a further object of the present invention to physically stabilize the tape pack during long term archival storage.
In carrying out the above objects and other objects and features of the present invention, a reel for holding tape is provided. The reel includes a hub with a cylindrical surface about which the tape is wound to form a tape pack. Flanges are fixed to either end of the hub, forming parallel inner surfaces. At least one of the inner surfaces has a compliant raised pattern. In various embodiments, the raised pattern may include ridges extending radially from the hub outward, segments extending radially from the hub across a portion of the flange inner surface, or a plurality of blisters.
In an embodiment of the present invention, the raised pattern is made from at least one embossed polymer sheet. In another embodiment, the raised pattern is formed on the flange inner surface.
In an aspect of the present invention, the raised pattern defines a plurality of compliant tape contacting surfaces providing an aligning forced to the tape edge as the tape edge is wound into the tape pack. In another aspect of the present invention, the raised pattern defines a plurality of channels allowing air to escape from between the tape and the tape pack as the tape is wound into the tape pack. In still another aspect of the present invention, the raised pattern defines a plurality of compliant sides reducing the possibility for damage to the tape in the tape pack due to shock received by the reel.
A liner surface for a tape reel having two parallel flanges separated by a cylindrical hub is also provided. The liner surface is positioned between the tape pack and either or both of the tape flanges. The liner surface covers the surface of the flange extending over the tape pack. The liner surface has a raised pattern separating the pack from the flange.